It is generally acknowledged that performance in various motor skills can be significantly affected by the participant’s focus of attention, induced by instructions for instance. However, the effect of focus of attention in relation to strength training exercises remains to be investigated. PURPOSE: To address the effect of internal and external focus of attention on the surface electromyography (EMG) amplitude during bench press. METHODS: Twenty-one young male individuals (age 25 ± 2 years) with at least two years of strength training experience (3 repetition maximum (3RM) in bench press 109 ± 25 kg) voluntarily participated in this study. Participants performed a 3RM maximum test followed by a set of 3 repetitions at 75% of 3RM and three sets of eight repetitions in bench press at 60% of 3RM. This task was executed in three experimental conditions: (1) without any specific instruction concerning the focus of attention (NOI), (2) with an internal focus of attention on the contraction of the pectoral muscle (INT), and (3) with an external focus of attention on the movement of the bar (EXT). The order of (2) and (3) were randomized. EMG data was recorded from 13 muscles, i.e. 7 from the upper body and 6 from the lower body. Each EMG envelope was normalized with respect to the EMG data recorded at 75% of 3RM and the average EMG amplitude was calculated. RESULTS: The average normalized EMG amplitude values were significantly higher for EXT than NOI for pectoralis major (PM) 44±16 vs. 40±16%, anterior deltoideus (DA) 43±18 vs. 38±17%, triceps brachii medial head (TBM) 40±19 vs. 35±17%, latissimus dorsi (LD) 40±17 vs. 36±16%, and erector spinae (ES) 24±15 vs. 22±14% (p≤0.05 for all). The average normalized EMG amplitude values were significantly higher for INT than NOI for DA 43±18 vs. 38±17%, biceps brachii (BB) 30±18 vs. 28±16%, TBM 40±19 vs. 35±17%, LD 43±18 vs. 36±16%, and ES 27±17 vs. 22±14% (p≤0.05 for all). In other words, the EMG amplitude increased in 6 of 7 muscles of the upper body, when an external or internal focus of attention was applied as compared to a control condition. CONCLUSIONS: The present findings indicate that adopting an internal or external focus of attention significantly increases the EMG amplitude in muscles of the upper body during bench press when compared to a control condition.